This invention relates generally to the field of capture or containment devices used to capture and retain liquids, particularly leaks or spills from other containers, where the capture device is provided with a removable cover when not in use. More particularly, the invention relates to such devices which are primarily designed for outdoor use, where the cover is used to prevent rain water from entering the capture device. Even more particularly, the invention relates to such devices which are designed for placement in the center of a railroad track to capture liquids falling from railroad cars positioned above the devices.
It is often desirable to provide a liquid containment device beneath liquid containers or beneath areas where liquids are being sprayed or used, so that any liquid, whether from spills, leaks, run-offs or the like, is captured and retained by the containment device rather than allowing it to fall onto the floor or ground. This is especially desirable when the liquid is environmentally hazardous to the extent that non-containment can result in contaminated soil or water supplies, hazardous conditions for people or animals, etc. One such situation where it is most desirable to capture liquid leaks or spills to prevent ground contamination and fouling are railroad transfer stations, such as a rail siding where tanker cars are loaded, unloaded or cleaned.
A known solution is to provide a generally rectangular capture tray or pan which is sized to fit between the parallel rails making up a single track, the tray having short vertical side walls. Because the tray will capture hazardous materials such as chemicals, oil, grease, etc., the tray is preferably provided with a removable or translatable cover to prevent rain water from entering the tray when the tray is not in use. This precludes the possibility of a heavy rainfall amount filling the tray to reduce the available volume of the pan and ultimately washing over the side walls, which would disperse any hazardous liquids into the environment. Examples of such devices can be seen in U.S. Pat. No. 4,651,887 to Patrick, U.S. Pat. No. 5,435,458 to Bishop, U.S. Pat. No. 5,492,158 to Haag and U.S. Pat. No. 5,775,869 to Bishop. The Patrick patent shows a rectangular structure having a centrally located drain and a hinged drain surface, the surface being made of two planar members joined along the center line by a hinge. The surface can be disposed above the horizontal such that the two members define an elevated ridge line or peak, in which case liquid such as rain water will be directed over the side walls, or the surface may be disposed below the horizontal such that the two members define an inwardly sloping configuration such that hazardous liquid will be directed into the drain. The Bishop '458 patent shows a system comprising a central rectangular capture tray positioned between the rails, the central tray having a peaked cover, i.e., sloping to either side from a central elevated ridge line, which is translated in the direction parallel to the rails to uncover the central tray for use. Exterior rectangular trays are positioned to the outside of each rail, the exterior trays having a pair of hinged covers which provide a peaked central ridge line in the closed configuration. One of the hinged covers opens to cover rail area adjacent the exterior tray and the other opens outward, such that liquids which fall onto the opened covers are directed into the exterior trays. When the trays are not in use and the covers are in place, rain water is directed to the sides of the trays. The Haag patent discloses a system of rectangular trays which utilize absorbent pads retained within and overlapping adjoining trays. Haag does not discuss the use of covers, and no means are provided in Haag to address the problem of the gap between the sides of the pans and the rails themselves, probably due to the need to provide a space for the wheel flanges of the railroad cars. The Bishop '869 patent shows a central tray positioned between the rails with a pair of hinged covers showing a peaked central ridge in the closed configuration, where the covers open outward to extend beyond the rails laterally to capture and direct liquids into the tray. The tray has a stepped configuration such that its side edges are seated on top of the rails themselves. This device cannot be left in place between uses, since the device overrides the rails and prevents movement of the rail cars. Instead the device must be placed by fork lift under a rail car after it is moved into position and must be removed by a fork lift before the rail car can be removed. A problem with the Bishop '458 device is that the rail car must be correctly positioned relative to the trays so that the wheels do not interfere with the opening of the covers, which can only be accomplished after the rail car is in place as the covers overlie the rails. The main problem with the Patrick device is that the top of the drain surface will quickly become covered in oil, grease or other hazardous chemicals, which will be washed from the surface into the environment with each rainfall.
It is an object of this invention to provide a capture or containment pan or tray device which collects liquids falling from above the pan to prevent environmental damage, where the side walls of the pan do not interfere with the movement of rail cars when the device is positioned between the parallel rails of a railroad track, such that sealing gasket members can be placed between the side walls of the pan and the rails themselves to preclude passage of liquid between the rails and the pan, and further where the method of installation of the invention allows for the sealing gaskets to be disposed under compression. It is a further object of this invention to provide such a device where the tray is provided with a removable cover having an inverted or valley configuration such that the cover directs rain water into a centrally located drain which directs the water beneath the pan. It is a further object to provide such a device where the covers can be removed or replaced with a rail car located above the pan. It is a further object to provide such a device with internal grating so that workers can stand or walk over the pan and cover without contacting the liquid retained in the pan. It is a further object to provide connector fittings or conduits in the side walls of the pan so that adjoining pans can be connected in a liquid communicating manner so that liquid is able to flow from one pan to the next, or to allow for connection of removal conduits to pump or direct the liquid from the pan. These and other objects not expressly set forth will become obvious after review of the accompanying disclosure.